jacobsen



E. JACOBSEN. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FlLED MAR 21,1918- 1 ,332,217. Patented Mar. 2, 1920.

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APPLICATION FILED MAR. 2|. 1918.

1 ,3 3 2,2 1 7 Patented Mar. 2, 1920.

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v fmrenfmr Emd JED/155521 ITIJEUEQ UNITED STATES PATENT OFFICE.

EMIL JACOIBSEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Application filed March 21, 1918.

To all ir/mm it may concern:

Be it known that I, EMIL Jaconsnn, a citizen of the United States of America, and a resident of Chicago, Cook county, and State 0)" Illinois, have invented certain new and usr-lul Improvements in. Automatic Tlcleyfiurne Systems, of which the following is a specification.

My invention relates in general to that type of systems-z in which automatic switches are used to establish a connection between a pair oi suliiscribers lines and in which the use of an operator is not required.

Among the objects of my invention are to provide improved circuits for repeating impulses from a repeater in one exchange to an automatic switch in another exchange where a plurality of exchanges are employed and to arrange the impulsing circuit so that a uniform impulse will always be delivered to the automatic switch irrespective of the length cl. trunk line over which the impulses are repeated.

In a system of this character it is often desired to give a subscriber in one exchange access to subscribers in a number of other exchanges, the trunk lines leading to such exchanges being of dilierent lengths. In such a system my invention will be particularly valuable as a relay ot' the ordinary type cannot adjust itself to deliver unijl orm impulses over trunk lines oil ditlercut resistance.

In the drawings Figure 1 shows a calling subscriber A having access through the medium of the usual well known rotary line switch (I to a selector repeater D which is used only for long distance calls. In practice one or more selector switches of the Keith Erickson type will be inserted between the line switch C and the selector repeater l) depending upon the size of the exchange and this selector will also have access to connectors for use in, calling local siv scribers. Fig. 2 shows a connector switch l) of the well known Keith Erickson type having access to called lines, one ot which called lines is shown at B.

T. will now describe the operation of the switches in establishing a connection from a subscriber A to a subscriber B.

When the subscriber at substation A, removes his receiver to initiate. a call the circuit ot the line relay 2 of line switch C is Specification of Letters Patent.

Patented Mar. 2, 192-0.

Serial No. 223,697.

closed in a well known manner by the switch hook springs 3 and l and through the calling device C. D. The relay 2 closes a series circuit for the switching relay 5 and rotary magnet 6 in series at springs 7 and also connects the private wiper 10 to a point between the relay 5 and magnet 6 by the operation of springs 11.. It the trunk upon which the line switch G is standing is busy, a ground will be connected to the private wiper which ground will short circuit the relay 5 to prevent its operation and cause the rotary magnet 6 to rotate the wipers 8, 9 and 10 to the next trunk line. Assuming the next trunk line to be idle, there will be no ground on the wiper 10 and the relay will therefore operate to disconnect the relay 2 and ground from the line of substation A, and the private wiper 10 from the rotary magnet and to connect the line of substation A to the line relay 12 of the switch D through the wipers 8 and 9 by means of springs 18 and 1.4 and springs 15 and 16. The line relay 12 energizes over the line circuit through the substation A and closes a circuit for relay 17 at springs 18 and 19 and also closes a circuit for re lay 20 at springs 21. The relay 17 upon energizing connects a holding ground to the circuit of the relay 5 of line switch C before the relay 2 has disconnected "round therefrorm thereby holding relay 0 energized, and maintaining the trunk to the switch D busy at the private contact and its multiples. It will be understood as before stated that a selector switch may and will be in practice inserted between the switches C and D without in any way interferingwith the operation of the switches.

The subscriber at substation A will now operate his calling device in accordance with the first digit of the called number to inter rupt the circuit of line relay 12 a number of times. Each time the relay 12 deuergizes it completes a circuit for the vertical magnet 22 and the slow relay 23 which was prepared by the operation of relay 17 and operates said vertical magnet to step the wipers 24, 25 and .26 to some level of the banks in which trunk lines leading to the desired exchange terminate. The relay23, being slow acting, maintains its armatures attracted during the operation of the vertical magnet.

As soon as the wipers 24, 25 and 26 take their first vertical step, the of normal springs 27 and 28 close. The springs 28 prepare a circuit for the release magnet 29, and the springs 27 close a circuit for the rotary interrupter relay 30, extending from ground through springs 35, springs 36 and 37, springs 38 and 39, springs 27, and relay 30 to battery. Relay 30, in turn energizes to prepare a circuit for the rotary magnet 31 at the springs 32, closes a circuit for itself from ground through springs 33 and also connects the same ground to one end of the winding of relay 34. It will be seen that relay 34 is maintained short circuited during the operation of the vertical magnet by the closure of the springs 38 and 39 of relay 23 in the first instance and then by ground from springs 33 and will not energize. As soon as.the impulses for the first digit cease. the relay 23 will release its armatures and complete a circuit for the rotary magnet extending from ground through springs 35, springs 36 and 37, springs 38 and 40, springs 32, and magnet 31 to attery. The magnet 31 operates to step the wipers 24, 25 and 26 onto the first pair of contacts of the level to which the wipers have been raised and also opens the circuit for the rotary interrupter relay 30 at the springs 41. Belay 30 will also denergize to open its own locking circuit at springs 33, and open the circuit of magnet 31 at springs 32. The magnet 31 will therefore denergize to again, close a. circuit at springs 41 extending from ground through springs 35, relay 34, springs 41, and relay 30 to battery. Another branch of this circuit extends through the springs 42 and 43 to the private wiper 26. Therefore if this trunk line is idle and a ground is present thereat then the relay 34 will be still short circuited by this ground and a circuit will be closed directly for relay 30, which will again energize to close a circuit for the rotary magnet. This alternate operation of relays 30 and magnet 31 causes the wipers 24. 25 and 26 to be rotated until an idle trunk line leading to a connector H is found, at which time no ground will be present on the private contact and the relay 34 will be no longer short circuited. The relay 34 will therefore energize over the above tracedcircuit in series with the relay 30, which relay 30 will not energize, due to the comparatively high resistance of relay 34. The relay 34 upon energizing opens the circuit of the vertical magnet at springs 44, and closes a locking circuit for itself to the private wiper 26 independent of the ground from relay 17. The private wiper will be supplied with ground from the release relay of the switch ahead as soon as that switch is operated. The relay 34 also closes the springs 46 to cut the trunk line from substation A through to wipers 24 and 25 whereby a circuit is closed for the line relay 47 of connector switch E extending from ground through the lower winding of said relay, springs 48 and 49, trunk oonduc tor 50, wiper 25, springs 45, lower winding of relay 20, lower winding of relay 52. springs 53 and 54, upper winding of relay 55, springs 46, wiper 24, trunk conductor 51, springs 56 and 57, and upper winding of relay 47 to battery. The relay 47 energizes over this circuit and operates to close a circuit for the slow relay 58. The relay 58 also energizes to connect ground to the release trunk to hold the relay 34 of switch D energized through springs 59, 60 and 61.

Now when the subscriber at A operates his calling device for the next digit of the called number, the line relay 12 of switch D is operated in the same manner as for the first digit. At this time however, the circuits of the operating ma ets of switch D are open and the relay 20 1s operated b the line relay 12 to repeat the impulses 0 this digit to the line relay 47 of switch E. At the same time that the relay 20 is operated by relay 12, the slow relay 23 is operated from relay 12 to maintain its armatures attracted during the sending of impulses to thereby maintain the upper winding of relay 55 and the lower winding of relay 52 short circuited. The circuit over which impulses are delivered to relay 47 extends therefore over the previously traced circuit to wiper 25, thence through springs 45, lower winding of relay 20, springs 62, spn'n s 46, and wiper 24 over the rest of the a JOVG traced circuit. It will be remembered that the selector repeater D has access to a number of trunk lines which lead to a number of different exchanges and that these trunk lines in practice will vary a great deal in length, that is, in one call the relays 12 and 20 will be repeating impulses over a short trunk line to the line relay of a. connector while in another case the impulses will be repeated over a long trluik line. As is well known it is very difiicult to adjust a relay to send uniform impulses over both long and short trunk lines, and I have therefore provided the relay 20 which operates in an improved manner to take care of the varying conditions. The relay 20 has a pair of windings .which are wound to oppose each other. Now when a circuit is closed for the upper winding-of said relay by relay 12, the relay will energize to close its springs 45 to'thereby close the above traced circuit of relay 47 through the lower winding of relay 20 in series. Now if the trunk line leading to connector E is short, and therefore of low resistance then a heavy current will flow through the lower winding of said relay 20. so that, when the circuit of relay 20 is again opened by relay 12, the heavy current flowing in the lower winding will cause the relay 20 to denergize immediately so that the impulse to relay l7 will be comparatively short. However if the trunk .leading to connector E is long and of high resistance then it will be seen that the lower winding of relay 20 will act more in the nature of a slug, and will not allow the. springs to be opened as quickly as when the trunk line is shorter. Therefore it will be seen that the relay 2O automatically adjusts itself to either long or short trunk lines. ()1? course the upper winding of re- 20 has a greater number of turns than the lower winding so that the current in the lower winding is never strong enough to cause the non operation of said relay. The relay 47 therefore receives a number of impulses and operates the vertical magnet 63 and slow series relay 6st in series to step the wipers 65, 66, and 67 to a level in which the desired line is located. The circuit for initially energizing relay 64; and magnet 63 extends through front contact of relay 58, springs 68, and relay 6% and magnet 63 to battery. As soon as the wipers step off normal, however, the springs 68 are opened and springs 69 are closed so that a new circuit is closed for relay Get and magnet 63 extending through springs 69, springs 70 and 71., relay 64, and magnet 63 to battery.

After the imrmlses for this digit cease the relay 64- will deenergize to permanently open its own circuit and to close a circuit for rotar magnet 73 at springs 70 and 72. lVheu the subscriber sends the impulses for; the next digit the relay 47 is again operated by the repeater relay 20 to open and close a circuit for the rotary magnet 73 through springs 74 and 7 5, springs 76 and 7 7, springs 69, springs 70 and 7 2, springs 7 8, where the circuit divides, one path extending through relay 7 S) to battery and the other through springs 80 and magnet 73 to battery. The magnet 7 :3 will therefore operate to rotate the wipers 65, 6G and 67 to the contacts of the desired line, while relay 7 9 will maintain. its armatures attracted during said impulses and for a short interval thereafter.

Should the called line be busy, a ground will be found by wiper 67 which will energize the relay Set through springs 83, 82 and 81. the springs 82 and 81 being held closed by relay 7 9 as stated. The relay 84. is the usual busy relay which operates to disconnect the ope 'ating magnets of the switch and connect a busy signal to the calling line so that the calling subscriber may release and call again.

Should the called line be idle, however, no ground will be found by wiper 67 and wiper 84, will therefoie not energize, and as soon as relay 75 falls back a circuit will be closed for the lower winding of relay 85 extending from ground at relay 58, through springs of relay 84, lower winding of said relay. springs 86 and 81, private wiper, and relay 87 and magnet 88 of line switch C to battery. The relays 85 and 8-7 only will energize over this circuit, relay 85 locking itself through its upper winding and closing the springs 89 and 90, and relay 87 disconnecting the operating magnets of. switch C from the called line. As soon as the springs 89 and 90 close a signaling circuit is completed for the called line from battery through the upper winding of ring cut off relay 91, springs 92 and 93, springs 89, to and through substation B, and back through springs 90. springs 9-1 and 95 to the armature of inter rupter relay 96, which relay operates to first connect the called line signaling circuit to generator R, and then to the booster battery B. As soon as the called subscriber responds by removing his receiver the relay pare certain release circuits so that the last man to restore his receiver will release the connector switch and will also operate to reverse the connections of line relay 47 to the conductors and 51 which will. also reverse the direction of the current flowing in relays .20, 52 and 55. The relay has heretofore not been energized as the two windings have opposed each other. Now, however, this relay will energize and close a circuit for the relay 98 which in turn operates to reverse the battery in the calling line for any purpose and to include the upper winding of relay 52 in series with its lower winding in the holding circuit of connector E. As soon as the conversation completed the connection will be released in the usual manner by the calling and called subscribers.

It will be seen therefore that l have provided a very simple and efficient method of supplying a uniform impulse to the line relay of an automatic switch over trunk lines of varying resistance.

Having fully described and ascertained my invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

What I claim as my invention is:

1. In a telephone system, a relay, a wind ing for energining said rel ay, another winding for said relay for retardii'ig the action thereof. autmnatic means for causing cur rents of various strengths to flow in said other winding, the retarding action of said other winding depending upon the strength of the current caused to flow through said other winding.

2. In a telephone system, a relay, a winding for energizing said relay, another winding for said relay for retarding the action thereof, a plurality of circuits of varying resistance, means for including said other winding in any one of said circuits, the retarding action of said other winding dependingupon the resistance of the circuit in wh it is included.

3. In a telephone system, a relay, a winding for energizing said relay, another winding for said. relay for retarding the action thereof, a plurality of circuits of varying resistance, means for including said other winding in any one of said circuits, the retarding action of said other winding varying in accordance with the resistance of the circuit in which it is included.

4. In a telephone system, a relay, a winding for said relay, a circuit for said winding, an interrupter or opening said circuit to cause said relay to denergize intermittently, another winding for said relay, a plurality of circuits of varying resistance, means for including said other winding in an one of plurality of circuits, said re ay controlled by the resistance of the circuit to which the other winding is connected to remain deenengized either a longer or a shorter interval of 5. In a telephone system, a relay, an impulse sender tor operating said rela at a uniform rate of speed a plurality o trunk lines of v g resistance, a winding for said relay a apted to be included in any one of said trunk lines to re at said impulses thereto, said relay contro led by the resistanee of the trunk to which said winding is connected through the medium of said second winding to shorten or lengthen the delivered.

.6. In a telephone system, an automatic switch, a relay associated with said switch, a winding for energizing said relay, another for said relay for retarding the action thereof, a plurality of trunk lines varying resistanm, means for controlling said automatic switch to connect said other winding in series with one of'said trunk lines, the retarding action of said other winding depending upon the resistance of said trunk line to which the windmg is connected.

In a telephone system, an automatic switch,tnunk lines of d-ifierent lengths, a relay for controlling said switch to connect with one ozf'said trunk lines, a second relay, a circuit for said relay controlled by said first. relay, means controlled by said second relay-tor repeating impulses to the connected trunk line, and m controlled by the length obtheconnee trunk line for varyithe duration ofeach of said impulses.

I. In a telephone system, an automatic switch, trunk lines of diflerent lengths,

for controlling saidswitch to connect with any one-of said trunk lines, a refor repeating impulses from a calling su 'ber s line to said trunk line, a winding included in-series with said trunk line, and semi winding controlled by the length of the trunk line to which the automatic switch connects for varying the dura- {ion of the impulses repeated to said trunk 9. In a telephone system, a calling subscribers line, an automatic switch, trunk lines of varying lengths accessible to said switch, a line relay controlled by impulses from said subscribers line for controlling the operation of said switch to connect with any one of said trunk lines, another automatic switch associated with each of said trunk lines, another relay controlled by said line relay to repeat impulses over any one of said trunk lines to operate the associated switch, a winding for said other relay, said winding-controlling said other relay to deliver unii'orm impulses to the switch associated with the connected trunk line irrespective of the length of said trunk line.

10. In a telephone system, a calling subscribers line, an automatic switch, trunk lines of varying lengths accessible to said switch, a line relay controlled by impulses from said subscribers line for controlling the operation of said switch to connect with any one of said trunk lines, another automatic switch associated with each of said trunk lines, a differential relay controlled by said line relay to repeat impulses over any one of said trunk lines to operate the associated switch, a windin for said differential relay, said winding controlling said differential relay to deliver uniform impulses to the switch associated to the connected trunk line irrespective of the length of said trunk line.

11. In a trunking system having a plurality of trunk lines of varying resistance each terminating in an automatic switch, an impulse sender, means for associating said sender with an one of said trunks to trans mit impulses t ereover to operate the associated switch, together with means for varying the character of said impulses dependmg upon the resistance of the connected trunk.

12. In a trunking system having a plurality of trunk lines of varying resistance each terminating in an automatic switch, an impulse sender, means for associating said sender with an one of said trunks to transmit impulses tliereover to operate the associated switch, together with automatic means for varying the character of said impulses dependin upon the resistance of the connected t 13. In a trunking system having a plurality of trunk lines of varying resistance each terminatin in an automatic switch, an impulse sen r, means for associating said sender with any one of said trunks to transmit impulses thereover to operate the associated switch, together with means for varying thecharacter of said impulses depending upon the resistance of the connected trunk, said last means including a magnet for operating said impulse sender.

14. In. a trunking system having a plurality of trunk lines of varying resistance each terminating in an automatic switch, an impulse sender, means for associating said sender With any one of said trunks to transmit impulses thereover to operate the 10 associated switch, together with means for varying the character of said impulses depending upon the resistance of the connected trunk, said last means including a magnet for operating said impulse sender, said magnet having a coil Which is energized over the connected trunk.

Signed by me at Chicago, Cook county, Illinois, this 13th day of March, 1918.

EMIL J ACOBSEN. 

